Abstract

Precoded orthogonal frequency division multiplexing (Precoded-OFDM) and vector-OFDM (VOFDM) systems was proposed to eliminate channel spectral nulls and reduce the cyclic prefix length by V times in a single transmit antenna systems, respectively. However, the insertion of one or more zeros between each two sets of V consecutive information symbols in precoded-OFDM expands the data rate overhead of the system hence high Peak to Average Power Ratio (PAPR). VOFDM system does not shown good performance in the spectral nulls channels. This study merges the VOFDM with carrier interferometry code (CI-VOFDM) to improve the performance of OFDM system in intersymbol interference (ISI) channel. The simulation results show a great improvement in terms of Bit Error Rate (BER) performance in the CI-VOFDM system.